Hi,
When playing analogue audio on my P4P800s se i
intermittently get pops and clicks (seems to be a common
problem to do with clipping) and I also get a constant
low buzzing and noise when for example the HDD reads, I
minimize a window or move the mouse.
I wanted to know that if I bought a digital receiver and
speakers and used the S/PDIF output would these two problems
not appear because the digital signal is just being
passed through and not touched by the soundmax?
Thanks
Onboard sound chips can support multiple analog outputs,
like 5.1 for example. Analog output is transparent in
the sense that no licensed software solution is required
to produce the sound.
SPDIF is a two channel solution. It is basically stereo.
Dolby labs created a compression scheme (AC3), to compress the
redundancy out of a 5.1 audio stream, so that it could be
fitted in the bandwidth of the two available SPDIF channels.
What this means is, you need a way to get a Dolby licensed
compression solution, if you want to use your digital receiver
for everything (5.1). Some of the new motherboards with Azalia
high definition audio chips, come bundled with Dolby software
to create AC3. If you play back DVD movies, there is an AC3
soundtrack that is sent unmodified to the SPDIF connector,
to achieve the same end. Software solutions produce perceptable
delay, which means if a Windows desktop alert sound went
through the compressor, the delay could be a second or so.
In short, your digital receiver idea is not a seamless
solution. A cheap sound card (Soundblaster or similar) will
give you multiple analog channels of output, without the
problems that seem to plague onboard sound. At least the
buzzing and humming should disappear.
About the best you can do inside the computer, is stop using
the CDROM analog cable, from the CD drive to the motherboard
CD header. (Use the DAE option, which extracts digital samples
over the IDE cable from the CD drive instead.) Any audio cables
strung inside the computer function as antennas, and the
interference is aliased down to voice band frequencies, and
that is a potential source of humming or buzzing.
Also, make sure when using the mixer panel, that any unused
analog inputs are muted, to eliminate them as sources of noise.
I get the occasional pop from my AD1985 soundmax solution, but
haven't traced down where they are coming from. The pops
don't correlate with loud output, so it probably isn't clipping,
but could be due to some kind of sample rate mismatch, or a
data overrun/underrun. The pops are not delivered at a constant
rate.
Sometimes bugs like this are due to the Southbridge. I think
there is an errata against the ICH2 for example, where the
AC97 input will miss an occasional sample. There should not be
a reason for that to happen in the output direction.
The motherboard with my Soundmax solution is not overclocked,
so any problems cannot be blamed on that.
So, I'd recommend a separate analog sound card. It doesn't have
to be expensive, to provide basic audio without fanfare. The
noise floor for audio recording should be much better as well.
And the sound card could be cheaper than buying a digital
receiver. Check the sound card documentation carefully before
buying, to see if it has bass/treble adjustment, as some
users are disappointed to find that doesn't work or doesn't
exist. Some onboard sound solutions have an adjustable
equalizer, but the time to check for that feature, is before
you buy.
HTH,
Paul
